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The term “antibiotics” is a broadly used misnomer to designate antibacterial drugs. In a recent article, we have proposed to replace, e.g., the term “antibiotics” by “antibacterial drugs”, “antibiosis” by “antibacterial therapy”, “antibiogram” by “antibacteriogram”, and “antibiotic stewardship” by “antibacterial stewardship” (Seifert and Schirmer Trends Microbiol, 2021). In the present article, we show that many traditional terms related to antibiotics are used much more widely in the biomedical literature than the respective scientifically precise terms. This practice should be stopped. Moreover, we provide arguments to end the use of other broadly used terms in the biomedical literature such as “narrow-spectrum antibiotics” and “reserve antibiotics”, “chemotherapeutics”, and “tuberculostatics”. Finally, we provide several examples showing that antibacterial drugs are used for non-antibacterial indications and that some non-antibacterial drugs are used for antibacterial indications now. Thus, the increasing importance of drug repurposing renders it important to drop short designations of drug classes such as “antibiotics”. Rather, the term “drug” should be explicitly used, facilitating the inclusion of newly emerging indications such as antipsychotic and anti-inflammatory. This article is part of an effort to implement a new rational nomenclature of drug classes across the entire field of pharmacology. Supplementary Information The online version contains supplementary material available at 10.1007/s00210-021-02144-9.

Heavy metals are known to possess toxic effect against prokaryotes as well as eukaryotes. Bacillus subtilis, a gram-positive bacterium, finds several useful applications such as biofertilization and antibiosis, but such applications get compromised due to limited bacterial survival during heavy metal stress. In the present study, experimental measures for natural adaptation of these bacteria to high Hg2+ concentration were performed by serially treating them with lower to higher Hg2+ concentration. Also, same adaptive ability and sustained growth were observed at high Hg2+ concentration after a year of induction thereby confirming adaptive success. Analysis of catalase and superoxide dismutase activity showed increased enzymatic activity as a means of survival under metal stress. Proteomic profiling was observed by SDS-PAGE indicating expression of differential proteins in adapted strains. Less malondialdehyde content in adapted strains showed restoration of membrane integrity which was also evident in SEM analysis showing smoother cell surface. Such successful adaptation induced in Bacillus subtilis paves way for agricultural and environmental applications of such strains in metal-stressed regions.

Screening of gut flora of the estuarine water fish ‘Chelon parsia’ for the presence of potential antibiotic producers resulted in finding a new strain Bacillus subtilis PP2. Further investigations focused on the active principle deduced that the molecule is a peptide class of antimicrobial agent with m/z of 1006.66. The culture condition optimization with improved combination and concentration of nitrogen and carbon sources had profound effect on bacterial growth as well as peptide production. In the preliminary stage of drug intervention, the partially characterized peptide antibiotic was found to be a broad-spectrum antifungal agent that can act against a number of fungal pathogens. The efficacy measurement indicated that the minimum inhibitory concentration (MIC) range of the peptide against various fungal pathogens ranges from 8.5 to 14.5 μg/mL. In terms of antibacterial activity, the molecule exhibits high efficacy, only in the narrow spectrum range. Antibacterial activity was observed against few bacterial pathogens with significantly pleasing MIC range (2.5 to 4.5 μg/mL) when compared with standard antibacterial drugs. The powerful surfactant property of the molecule opens up extended application into various fields. The novelty of the molecule is under investigation where the unique mass range (m/z 1006.66) of the molecule among the other peptide antibiotics produced by Bacillus subtilis is the key highlight. The findings of the present study suggest that the molecule can be proposed as a lead for the development of a multipurpose antimicrobial agent.

Clostridioides difficile infection (CDI) represents the leading cause of nosocomial diarrhea worldwide and is associated with gut dysbiosis and intestinal damage. Clostridium butyricum MIYAIRI 588 (CBM 588) contributes significantly to reduce epithelial damage. However, the impacts of CBM 588 on antibacterial therapy for CDI are not clear. Here we show that CBM 588 enhanced the antibacterial activity of fidaxomicin against C. difficile and negatively modulated gut succinate levels to prevent C. difficile proliferation and downregulate tumor necrosis factor-α (TNF-α) producing macrophages in the colon lumina propria (cLP), resulting in a significant decrease in colon epithelial damage. Additionally, CBM 588 upregulated T cell-dependent pathogen specific immunoglobulin A (IgA) via interleukin (IL)-17A producing CD4+ cells and plasma B cells in the cLP, and Th17 cells in the cLP enhanced the gut epithelial barrier function. IL-17A and succinic acid modulations with CBM 588 enhance gut colonization resistance to C. difficile and protect the colon tissue from CDI.

Streptococcus mutans produces bacteriocins that show antibacterial activity against several bacteria. However, comprehensive analysis of these bacteriocins has not been well done. In this study, we isolated 125 S. mutans strains from volunteers and determined their whole genome sequence. Based on the genome analysis, the distribution of each bacteriocin gene (mutacins I-IV, K8 and Smb) was investigated. We found 17, 5, and 2 strains showing 100% matches with mutacin I, mutacin II and mutacin III, respectively. Five mutacin III-positive strains had 2 mismatches compared to mature mutacin III. In 67 mutacin IV-positive strains, 38 strains showed 100% match with mutacin IV, while 29 strains showed some variations. In 23 mutacin K8- and 32 mutacin Smb-positive strains, all except one mutacin K8-positive strain showed 100% match with the mature peptides. Among 125 strains, 84 (65.1%), 26 (20.2%), and 5 (3.9%) strains were positive for one, two and three bacteriocin genes, respectively. Then, the antibacterial activity against oral streptococci and other oral bacterial species was investigated by using bacteriocin gene single-positive strains. Each bacteriocin gene-positive strain showed a different pattern of antibacterial activity. These results speculate that individual S. mutans strains may affect the bacterial composition of dental plaques.

The oral microbiome plays an important role in the human microbial community and in maintaining the health of an individual. Imbalances in the oral microbiome may contribute to oral and systemic diseases. The progression of periodontal disease is closely related to the growth of bacteria, such as Porphyromonas gingivalis, in the oral cavity. However, the pathogen growth mechanism specific to periodontal disease remains unknown. This study aimed to identify bacteria associated with periodontal health by focusing on hemolytic bacteria. Unstimulated saliva samples were collected from ten periodontitis patients and five healthy subjects to detect and identify the presence of hemolytic bacteria. The saliva of healthy subjects contained a higher proportion of G. haemolysans than saliva samples from patients with periodontitis. Growth inhibition assays indicated that the protein components contained in the culture supernatant of G. haemolysans directly suppressed the growth of P. gingivalis. This study shows that the presence of G. haemolysans in saliva is associated with periodontal health and that it inhibits the growth of P. gingivalis in vitro.

Background Probiotics are important tools in therapies against vaginal infections and can assist traditional antibiotic therapies in restoring healthy microbiota. Recent research has shown that microorganisms belonging to the genus Lactobacillus have probiotic potential. Thus, this study evaluated the potential in vitro probiotic properties of three strains of Lactiplantibacillus plantarum, isolated during the fermentation of high-quality cocoa, against Gardnerella vaginalis and Neisseria gonorrhoeae. Strains were evaluated for their physiological, safety, and antimicrobial characteristics. Results The hydrophobicity of L. plantarum strains varied from 26.67 to 91.67%, and their autoaggregation varied from 18.10 to 30.64%. The co-aggregation of L. plantarum strains with G. vaginalis ranged from 14.73 to 16.31%, and from 29.14 to 45.76% with N. gonorrhoeae. All L. plantarum strains could moderately or strongly produce biofilms. L. plantarum strains did not show haemolytic activity and were generally sensitive to the tested antimicrobials. All lactobacillus strains were tolerant to heat and pH resistance tests. All three strains of L. plantarum showed antimicrobial activity against the tested pathogens. The coincubation of L. plantarum strains with pathogens showed that the culture pH remained below 4.5 after 24 h. All cell-free culture supernatants (CFCS) demonstrated activity against the two pathogens tested, and all L. plantarum strains produced hydrogen peroxide. CFCS characterisation in conjunction with gas chromatography revealed that organic acids, especially lactic acid, were responsible for the antimicrobial activity against the pathogens evaluated. Conclusion The three strains of L. plantarum presented significant probiotic characteristics against the two pathogens of clinical importance. In vitro screening identified strong probiotic candidates for in vivo studies for the treatment of vaginal infections.

Lactic Acid Bacteria (LAB) regulate and maintain the stability of healthy microbial flora, inhibit the adhesion of pathogenic bacteria and promote the colonization of beneficial micro-organisms. The drug resistance and pathogenicity of Salmonella enteritis SE47 isolated from retail eggs were investigated. Meanwhile, Enterococcus faecalis L76 and Lactobacillus salivarius LAB35 were isolated from intestine of chicken. With SE47 as indicator bacteria, the diameters of L76 and LAB35 inhibition zones were 12 mm and 8·5 mm, respectively, by agar inhibition circle method, which indicated that both of them had inhibitory effect on Salmonella, and L76 had better antibacterial effect; two chicken-derived lactic acid bacteria isolates and Salmonella SE47 were incubated with Caco-2. The adhesion index of L76 was 17·5%, which was much higher than that of LAB35 (10·21%) and SE47 (4·89%), this experiment shows that the higher the bacteriostatic effect of potential probiotics, the stronger the adhesion ability; then Caco-2 cells were incubated with different bacteria, and the survival of Caco-2 cells was observed by flow cytometry. Compared with Salmonella SE47, the results showed that lactic acid bacteria isolates could effectively protect Caco-2 cells; finally, after different bacteria incubated Caco-2 cells, according to the cytokine detection kit, the RNA of Caco-2 cells was extracted and transcribed into cDNA, then detected by fluorescence quantitative PCR, the results showed that L76 could protect Caco-2 cells from the invasion of Salmonella SE47, with less cell membrane rupture and lower expression of MIF and TNF genes. Therefore, the lactic acid bacteria isolates can effectively inhibit the adhesion of Salmonella and protect the integrity of intestinal barrier.

Escherichia coli is a symbiotic bacterium in humans and animals and an important pathogen of humans and animals. Prevention and suppression of E. coli infection is of great concern. In this study, we isolated a strain of Lactobacillus agilis 32 from pig manure and evaluated its biological characteristics, and found that its bacterial survival rate was 25% after 4 h of treatment at pH 2, and under the condition of 0·5% bile concentration, its survival rate exceeds 30%. In addition, L. agilis 32 has a cell surface hydrophobicity of 77·8%, and exhibits 67·1% auto-aggregation and 63·2% aggregation with Enterotoxigenic E. coli 10 (ETEC 10). FITC fluorescence labelling showed that the fluorescence intensity of cecum was significantly higher than that of duodenum, jejunum or colon (P < 0·05), but no significant difference from ileum. Lactobacillus agilis 32 bacterial culture and CFS showed average inhibition zone diameters of 14·2 and 15·4 mm respectively. Lactobacillus agilis 32 CFS treatment can significantly reduce the pathogenicity of ETEC 10. These results show that L. agilis 32 is an active and potential probiotic, and it has a good antibacterial effect on ETEC10, which provides basic research for probiotics to prevent and treat intestinal diarrhoea pathogen infection.

From 98 Lactobacillus strains, isolated from Algerian homemade cheeses, 14 (B1-B14) were selected based on their anti-Escherichia coli and anti-Staphylococcus aureus activities. These strains were also tested towards Listeria monocytogenes 161 and Salmonella Typhimurium LT2 and further investigated for their resistance to simulated gastrointestinal digestion, cell surface properties, ability to adhere to HT-29 cells, cholesterol lowering, antioxidant activity, and technological traits. Five isolates (B9, B13, B18, B19, and B38) were active against L. monocytogenes and Salmonella. From them, three isolates, identified as Lactobacillus brevis (B9, B13, and B38) by MALDI-TOF spectrometry and 16S rDNA sequencing, exhibited high tolerance to pancreatic juice, bile salts and acidic juices, high percentages of hydrophobicity (87, 92, and 81%, respectively), auto-aggregation (61, 68, and 72%, respectively), and adherence to HT-29 cells (79, 84, and 74%, respectively), which testify on their potential of colonization of the human intestine. On the other way, the strains B9 and B13 manifested the most relevant antioxidant activity and cholesterol-lowering ability, respectively. L. brevis strains showed low acidifying and good proteolytic activities with noticeable heat tolerance. The results gathered in this study highlighted the richness of Algerian artisanal cheeses on new lactobacilli strains with an excellent probiotic potential and demonstrated that L. brevis, largely used as nonstarter in cheese manufacture, could be exploited also as a probiotic for human use.

Background Specific probiotic bacteria may have inhibitory effects against oral pathogens. Lactobacillus spp. have been researched worldwide and are used in probiotics, but due to difficulties with laboratory cultivation of and experimentation on oral microorganisms, there are few reports of Lactobacillus spp. being isolated from the oral cavity and tested against oral pathogens. This research aimed to determine the safety and inhibitory impacts of L. gasseri HHuMIN D as a potential oral probiotic with biotherapeutic capabilities against oral pathogens. Results The microbial and genetic characteristics of L. gasseri HHuMIN D were evaluated in this research. A 5% dilution of L. gasseri HHuMIN D culture supernatant exhibited 88.8% inhibition against halitosis-producing anaerobic microorganisms and L. gasseri HHuMIN D exhibited powerful inhibitory effects on the growth of every harmful oral bacterium tested. Unfortunately, other oral bacteria affected the growth of L. gasseri HHuMIN D, suggesting a poor proliferative response to most co-cultures. Hydrogen peroxide production by L. gasseri HHuMIN D reached 802 µmol/L after 12 hours and gradually diminished until 24 hours. It efficiently aggregated with P. catoniae and S. sanguinis, and completely supressed S. mutans-manufactured artificial dental plaque. L. gasseri HHuMIN D’s KB cell adhesion capacity was 4.41 cells per cell, and the cell adhesion of F. nucleatum and S. mutans diminished strongly in protection and displacement assays. L. gasseri HHuMIN D was evaluated for safety using ammonia and biogenic amine development, hemolytic property and mucin degradation testing, antibiotic susceptibility, and whole genome sequencing (WGS). Conclusion Our results suggest that L. gasseri HHuMIN D may be a safe, bioactive, lactobacterial food ingredient, starter culture, and/or probiotic microorganism for human oral health.

AIMS This research investigated the influence of soil microbiota on Escherichia coli O157:H7 survival in soil rinse and artificial soil. Additionally, the influence of selected soil bacteria on E. coli O157:H7 in soil environments was determined. METHODS AND RESULTS Escherichia coli O157:H7 counts (log CFU per ml or g-1 ) were determined by spread plating: (i) artificial soil amended with soil rinse (filter-sterilized and unfiltered) at 30°C; (ii) unfiltered soil rinse (50 ml) treated with cycloheximide (200 μg ml-1 ), vancomycin (40 μg ml-1 ), heat (80°C, 15 min) and no treatment (control) for 7 days at 30°C and (iii) filtered soil rinse with selected soil bacterial isolates over 7 days. There was a significant difference (P = 0·027) in E. coli O157:H7 counts after 35 days between artificial soils amended with filtered (4·45 ± 0·29) and non-filtered (1·83 ± 0·33) soil rinse. There were significant differences (P

The wild cochineal, Dactylopius opuntiae (Cockerell), has become the main pest of the prickly pear [(Opuntia ficus-indica (L.) Miller] cactus crop in most of the Mediterranean countries, including Morocco since 2014. The use of D. opuntiae-resistant cactus ecotypes seems to be one of the most practical management option for the control of this pest. The objectives of this study were to identify the resistant genotypes and to determine the mechanism of resistance in 10 D. opuntiae-resistant cactus genotypes. From O. ficus-indica cochineal resistance screening experiments conducted in the laboratory and in mesh cages, 10 cactus genotypes that had fewer nymphs attached with no further developmental changes in the insect were identified. Studies on resistance mechanism showed that resistant genotypes of O. ficus-indica had significantly fewer D. opuntiae nymphs compared with susceptible genotypes. Genotypes 311 and 322 were the least preferred by D. opuntiae with 24.66 and 30 nymphs found after 72 h of infestation. All resistant genotypes have higher levels of dead nymphs compared with the susceptible control. The difference in the mean number of dead nymphs among the different genotypes tested and the control was highly significant. All nymphs produced on resistant genotypes died at first instar stage, indicating that these genotypes possess antibiosis as a mechanism of resistance. Genotype 295 had the highest number of dead nymphs, indicating a strong effect of antibiosis to D. opuntiae. Our study showed that both categories (antibiosis, antixenosis) play a role in resistance of the Moroccan cactus ecotypes.

Dihydropyriculol is a major secondary metabolite of Pyricularia oryzae. However, the biological activity of dihydropyriculol has not been reported. Here, we showed that dihydropyriculol has inhibitory activity against Streptomyces griseus. Localization analysis of dihydropyriculol revealed that dihydropyriculol could reach to S. griseus under confrontation culture. These results suggest that dihydropyriculol can be used as a chemical weapon against S. griseus.

Made available in DSpace on 2021-06-26T02:53:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-06 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Severe attacks of Brevicoryne brassicae (Hemiptera: Aphididae) on brassica crops may lead to a significant decrease in yield and can cause plant death. Host plant resistance is considered a valuable tool in integrated pest management and can assist in reducing the damage caused by aphids. This study evaluated the behavioral and biological parameters of B. brassicae in 37 Brassica oleracea (L.) var. acephala genotypes, and aimed to characterize the mechanisms of antixenosis and/or antibiosis. In antixenosis, plants were arranged in a circle inside an arena, releasing to the center one hundred adult aphids. The number of insects was evaluated at 1, 2, 3, 6, and 24 h after infestation. For antibiosis, 30 adults were confined inside each clip-cage on each genotype. The total number of nymphs; number of nymphs per adult per day; total nymphs until 10 d after the first nymph had been produced; duration of the pre-reproductive phase; duration of the reproductive phase; nymphal survival; adult longevity; nymph-adult period and nymphal mortality at 5, 7 and 10 d were evaluated. Several genotypes showed be less infested and more harmful to B. brassicae on collard greens. The genotypes 20T, 24X, 18R, 22V, 15O, 19S, 27VA, and 17Q were the least infested in the antixenosis 24 h free-choice test. 2B, 5E, 8H, 19S, 21U, 27VA, 30OP, PE, MGH, and TP genotypes prevented B. brassicae from completing nymphal period, indicating antibiosis and/or antixenosis expression. 4D, GAU, 20 T, 14 N, and MGI genotypes prevented the aphid from reaching the reproductive phase. These genotypes may be useful for breeding programs that focus on the resistance of collard greens to aphids. Sao Paulo State Univ, Sch Agr, Dept Crop Protect, BR-18610034 Botucatu, SP, Brazil Univ Sao Paulo, Luiz de Queiroz Coll Agr, Dept Entomol & Acarol, BR-13418900 Piracicaba, SP, Brazil Sao Paulo State Univ, Sch Agr, Dept Crop Protect, BR-18610034 Botucatu, SP, Brazil CAPES: 001

Faba bean (Vicia faba L.) is a grain legume widely cultivated in many countries for food and animal feed. The faba bean stem borer (Lixus algirus L.) (Coleoptera: Curculionidae) is considered one of the major biotic stresses of faba bean in some Mediterranean areas, including Morocco. The use of genetic resistance is the most economical and environmentally friendly control method of insect pests. Therefore, a set of 233 faba bean genotypes from two ICARDA sets (GCP Ref.Set-2015 and AYT-2015) was evaluated for resistance to L. algirus under open field and net cage conditions at Douyet and Marchouch Stations in Morocco. Twelve genotypes (11 from the GCP Ref.Set-2015 and one from AYT-2015) showed a low level of infestation by the stem borer in the field and under cages. The results of free-choice screening showed a significant egg-laying preference of stem borer for the susceptible cultivars Defes and Alfia, compared with the two germplasm accessions IG 11561 and IG 72498. The accession IG 72498 expressed the highest level of antibiosis; with 100% mortality of first or second instars, with no adult exit holes on any of the plants checked. These two accessions are being used in the ICARDA crossing program to develop recombinant inbred lines to study the genetics of resistance to faba bean stem borer. This is the first report of resistance to stem borer in faba bean with antixenotic and antibiotic categories of resistance.

Made available in DSpace on 2021-06-25T11:58:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Aphis gossypii Glover (Hemiptera: Aphididae) is a polyphagous species frequently associated with the presence of sooty mold and viruses lethal to plants. The purpose of this work was to characterize possible resistance categories of cotton genotypes against A. gossypii. Initially, a preliminary test was carried out with 78 genotypes, 15 of which were selected for infestation ability assays and the determination of the cumulative aphid-day rates. Posteriorly, these genotypes were also evaluated through antixenosis and antibiosis assays. The genotypes FM 910, FM 966 LL, Moco, Gossypium hirsutum var. punctatum L. (Malvaceae), Variedade Reba = BTK-12, Deltapine, Hi-Bred, Acala 4-42, IAC PV010-1664, IAC 21, Reba B-50 PR and FMT 709 inhibited the aphid colonization. In the infestation ability assay, G. hirsutum punctatum, IAC PV010-1664 and Acala 4-42 were the least infested. In a multiple-choice assay, Deltapine Smooth Leaf and Variedade Reba = BTK-12 were significantly less infested, suggesting antixenosis. In the antibiosis assay, Gossypium arboreum L. (Malvaceae) 1 showed the lowest number of nymphs, number of nymphs per adult per day and, number of nymphs at 10 d after the birth of the first nymph in addition to reducing the reproductive period, nymphal survival, adult longevity and, developmental time. In the FM 910, the number of nymphs produced per day and, at 10 d after the birth of the first nymph decreased, which also indicated resistance. The results obtained here are unprecedented and can be explored in breeding programs to develop insect-resistant cotton cultivars. Sao Paulo State Univ, Sch Agr, Dept Crop Protect, BR-18610034 Botucatu, SP, Brazil Fed Univ Grandes Dourados, Dept Entomol & Biodivers Conservat, BR-79825070 Dourados, MS, Brazil Sao Paulo State Univ, Sch Agr, Dept Econ Sociol & Technol, BR-18610307 Botucatu, SP, Brazil Univ Sao Paulo, Coll Agr, Dept Entomol & Acarol, BR-13418900 Piracicaba, SP, Brazil Sao Paulo State Univ, Sch Agr, Dept Crop Protect, BR-18610034 Botucatu, SP, Brazil Sao Paulo State Univ, Sch Agr, Dept Econ Sociol & Technol, BR-18610307 Botucatu, SP, Brazil CNPq: 141953/2014-4 CNPq: 302831/2010-0 CNPq: 303892/2016-1 CAPES: 001

Made available in DSpace on 2022-04-28T19:47:40Z (GMT). No. of bitstreams: 0 Previous issue date: 2022-04-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Bemisia tabaci (Genn.) MEAM1 (Middle East-Asia Minor) (Hemiptera: Aleyrodidae) is an important pest of collards, Brassica oleracea var. acephala. This insect reaches high levels of infestation in the field, causing direct damage to plants, compromising productivity. Concerns related to chemical control have resulted in a search for alternative methods to manage populations of B. tabaci in the field. The use of resistant genotypes is a potentially and a valuable strategy to manage this insect, reducing its populations below the level at which it causes economic damage. This work evaluated period of incubation, duration of each instar, nymphal period, nymphal survival, development egg-adult, and adult longevity of B. tabaci MEAM1 on 13 collard genotypes under laboratory conditions after a previous screening involving 32 genotypes for oviposition non-preference. The following parameters were determined: duration period per instar, total nymphal period, nymphal survival, total development period (egg-adult) and adult longevity. The genotypes P1C, MG and LG expressed antibiosis and/or antixenosis against B. tabaci MEAM1, prolonging the total development period (egg-adult) of the insect. IMAN W, MOP and VE reduced the nymphal survival of the whiteflies, indicating some potential for resistance. Due to the importance of collards cultivation and the substantial damage potential that this insect presents to the crop, the selection of resistant genotypes is promising and may represent a useful tool for the management of whitefly in crops. Our results will contribute to genetic improvement programs for brassicas focusing on resistance to B. tabaci MEAM1. School of Agriculture Department of Crop Protection São Paulo State University Luiz de Queiroz College of Agriculture Department of Entomology and Acarology University of São Paulo School of Agriculture Department of Crop Protection São Paulo State University CAPES: 001 CNPq: 305991/2020

Background Eleven Lactobacillus (L.) strains were newly isolated from traditional Turkish Tulum cheeses and were characterized regarding their potential probiotic characteristics (bile and acid tolerance, gastric and pancreatic juice tolerance, lysozyme tolerance, adhesion ability), virulence determinants (hemolytic activity, antibiotic resistance, biogenic amine production), and functional properties (antibacterial activity, β-galactosidase activity, production of exopolysaccharides, cholesterol removal). Results These isolates were identified as L. brevis, L. plantarum, L. paracasei, L. coryniformis, L. rhamnosus and L. helveticus by 16S rRNA sequencing. With regard to safety aspects, none of the tested Lactobacillus isolates showed hemolytic activity or biogenic amine production. All the Lactobacillus isolates except isolate 24 were found to be sensitive or intermediate sensitive to penicillin, which is a frequently used antibiotic. Nine Lactobacillus isolates showed antibacterial activity against Staphylococcus aureus ATCC 25923, while only isolates 15 and 449 exhibited inhibitory activity against Listeria monocytogenes ATCC 7644. All isolated strains survived, even in the presence of 10.00 g L-1 bile after 48 h, and exhibited good survival at pH 3, but only two isolates survived at pH 2. Among the strains, isolate 15 exhibited satisfactory auto-aggregative, cell-surface hydrophobicity features, cholesterol-lowering activity and good acid tolerance. Isolate 15 also showed the strongest bile and simulated pancreatic juice resistance and moderate lysozyme tolerance. Conclusion These outcomes suggest that isolate 15, identified as a L. plantarum strain from Tulum cheese, may be a promising probiotic candidate and could be suitable for use in several fermented foods. © 2020 Society of Chemical Industry.

Made available in DSpace on 2021-06-25T10:15:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-02-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Middle East Asia Minor 1 is one of the most important pests of the common bean, due to its potential of causing direct and indirect damage. This study aimed to evaluate 78 bean genotypes to verify the occurrence of resistance of antixenosis type against B. tabaci. Initially, multiple-choice trials were performed to evaluate the oviposition preference and nymphs’ establishment at 3 and 15 days after infestation. Subsequently, 21 bean genotypes were selected, and a no-choice test was conducted. Colorimetric analyses were performed to establish correlations between leaf color and insect establishment. In multiple-choice trial, the genotypes BRS Ametista, BRS Estilo, BRS Esplendor, SCS 204 Predileto, BRS Notável, IPR Eldorado, CHIB 06, IPR Quero-Quero, Iapar 81, CHIP 338, IPR Garça, Arcelina 4, SCS 202 Guará, IAC Esperança, H96102-1-1-1-52, CHIP 348, Carioca Comum, CHIP 300, IAC Carioca Eté, IAC Ybaté, and Tybatã were the least used for oviposition and nymph establishment, demonstrating antixenosis or antibiosis. In the no-choice trial, most genotypes were less attractive to whitefly, and the genotypes CHIB 06, IPR Garça, CHIP 300, and IAC Esperança had less oviposition. The most attractive genotypes presented high luminosity and more intense green and yellow colors, indicating positive correlation. Therefore, the genotypes BRS Ametista, SCS 204 Predileto, BRS Estilo, IPR Eldorado, SCS-202 Guará, Carioca Comum, Arcelina 4, CHIP 348, and IAC Esperança showed the highest resistance stability in the no-choice trial, and they are promising sources of antixenotic factors for use in breeding programs to obtain whitefly-resistant common bean lines. Dept of Crop Protection School of Agriculture São Paulo State Univ (FCA/UNESP) Research Center for Family Agriculture Agricultural Research and Rural Extension Company of Santa Catarina (CEPAF/EPAGRI) Department of Entomology and Acarology Luiz de Queiroz College of Agriculture University of São Paulo (ESALQ/USP) Dept of Crop Protection School of Agriculture São Paulo State Univ (FCA/UNESP) CAPES: 001

Twenty three fungal endophytes isolated from desi cotton (Gossypium arboreum) were evaluated against two important pathogens of cotton Corynespora cassiicola and Fusarium solani, causal agents of leaf spot and seedling rot respectively. The internal transcribed spacer (ITS) region analysis was used for species-level identification of the fungal endophytes, wherein Curvularia (11) genus followed by Nigrospora (4) was found dominant whereas, Alternaria sp. (2) and Setosphaeria rostrata (2) were other prominent endophytes. Two isolates of Nigrospora sphaerica (CEL 5 and CEL 19) were highly efficient against C. cassiicola and inhibited mycelial growth up to 49.38% and 46.30%, respectively, whereas another isolate of N. oryzae (CEL 2) was effective against F. solani with inhibition of 43.06%. Besides, N. sphaerica (CEL 19) was found to influence the growth of test pathogens when tested for antibiosis. Through GC/ MS analysis of CEL 19 isolate, four major antimicrobial volatile organic compounds (VOCs), namely 1, 3‑diethyl benzene, 1, 4-diehtyl benzene, m-Ethylacetophenone, and p-cymene-7-ol were identified. The phylogeny tree constructed based on ITS sequences revealed two major branches and the first major branch consisted of most of the isolated fungal endophytes, whereas the second major branch consisted of only Coprinopsis cinerea and Puccinia chunjii. The 23 isolates divided into Ascomycota and Basidiomycota phyla were represented by four classes; Agaricomycetes, Eurotiomycetes, Sordariomycetes and Dothidiomycetes which were distributed into six orders. The majority of endophytes belonged to class Dothidiomycetes, followed by Sordariomycetes. There was no much difference observed between the endophytes and the reference taxa, even though it was a pathogen, indicating that pathogenicity of an organism is always not correlated with its gene sequence. Our findings suggest that N. sphaerica could be used as a potential biocontrol agent and its VOCs also have a role in suppressing the growth of plant pathogens.

Aims This study aimed to isolate actinomycetes from marine environments and examine their antifungal activity against Talaromyces marneffei both in vitro and in vivo. Methods and results Nineteen out of 101 actinomycete extracts were active and further determined for their minimum inhibitory concentrations (MIC). Three extracts of AMA50 that isolated from sediment showed strong antifungal activity against T. marneffei yeast (MICs ≤0·03-0·25 µg ml-1 ) and mould (MICs 0·5-16 µg ml-1 ) forms. The hexane extract from the cells of AMA50 (AMA50CH) exhibited the best activity against both the forms (MIC ≤ 1 µg ml-1 ). Three extracts from AMA50 killed the melanized yeast cells at 0·5 µg ml-1 . The AMA50CH was further tested for protective effects in Caenorhabditis elegans model. At concentrations of 1-8 µg ml-1 , the AMA50CH prolonged survival of T. marneffei-infected C. elegans with a 60-70% survival rate. The composition of AMA50CH was determined by gas chromatography-mass spectrometry. The major components were n-hexadecanoic acid, tetradecanoic acid and pentadecanoic acid. Sequencing analysis revealed that isolate AMA50 belonged to the genus Streptomyces. Conclusions The AMA50CH from Streptomyces sp. AMA50 was the most effective extract against T. marneffei. Significance and impact of the study Talaromyces marneffei is one of the most important thermally dimorphic pathogenic fungi. These results indicated the potency of marine-derived actinomycete extracts against T. marneffei both in vitro and in vivo.

Marine obligate actinobacteria produce a wide variety of secondary metabolites with biological activity, notably those with antibiotic activity urgently needed against multi-drug-resistant bacteria. Seventy-five marine actinobacteria were isolated from a marine sediment sample collected in Punta Arena de La Ventana, Baja California Sur, Mexico. The 16S rRNA gene identification, Multi Locus Sequence Analysis, and the marine salt requirement for growth assigned seventy-one isolates as members of the genus Salinispora, grouped apart but related to the main Salinispora arenicola species clade. The ability of salinisporae to inhibit bacterial growth of Staphylococcus epidermidis, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacer baumannii, Pseudomonas aeruginosa, and Enterobacter spp. was evaluated by cross-streaking plate and supernatant inhibition tests. Ten supernatants inhibited the growth of eight strains of S. epidermidis from patients suffering from ocular infections, two out of the eight showed growth inhibition on ten S. epidermidis strains from prosthetic joint infections. Also, it inhibited the growth of the remaining six multi-drug-resistant bacteria tested. These results showed that some Salinispora strains could produce antibacterial compounds to combat bacteria of clinical importance and prove that studying different geographical sites uncovers untapped microorganisms with metabolic potential.

Green mould disease of mushroom, Agaricus bisporus,is caused by Trichodermaspecies and can result in substantial crop losses.Label free proteomic analysis of changes in the abundance of A. bisporusproteins following exposure to T. aggressivumsupernatantin vitroindicated increased abundance of proteins associated with an oxidative stress response (zinc ion binding (+6.6 fold); peroxidase activity (5.3-fold); carboxylic ester hydrolase (+2.4 fold); dipeptidase (+3.2 fold); [2Fe-2S] cluster assembly (+3.3 fold)). Proteins that decreased in relative abundance were associated with growth: structural constituent of ribosome, translation (-12 fold), deadenylation-dependent decapping of nuclear-transcribed mRNA (-3.4 fold), and small GTPase mediated signal transduction (-2.6 fold). In vivoanalysis revealed that 10-4 T. aggressivuminoculum decreased the mushroom yield by 29% to 56% and 10-3 T. aggressivuminoculum decreased the mushroom yield by 68% to 100%. Proteins that increased in abundance in A. bisporusin vivofollowing exposure to T. aggressivumindicated an oxidative stress response and included proteins with pyruvate kinase activity (+2.6 fold) and hydrolase activity (+2.1 fold)). The results indicate that exposure of A. bisporusmycelium to T. aggressivum in vitroand in vivoresulted in an oxidative stress response and reduction in growth.

The over-prescription of antibiotics for treatment of infections is primarily to blame for the increase in bacterial resistance. Added to the problem is the slow rate at which novel antibiotics are discovered and the many processes that need to be followed to classify antimicrobials safe for medical use. Xenorhabdus spp. of the family Enterobacteriaceae, mutualistically associated with entomopathogenic nematodes of the genus Steinernema, produce a variety of antibacterial peptides, including bacteriocins, depsipeptides, xenocoumacins and PAX (peptide antimicrobial-Xenorhabdus) peptides, plus additional secondary metabolites with antibacterial and antifungal activity. The secondary metabolites of some strains are active against protozoa and a few have anti-carcinogenic properties. It is thus not surprising that nematodes invaded by a single strain of a Xenorhabdus species are not infected by other microorganisms. In this review, the antimicrobial compounds produced by Xenorhabdus spp. are listed and the gene clusters involved in synthesis of these secondary metabolites are discussed. We also review growth conditions required for increased production of antimicrobial compounds.

Lactic acid bacteria (LAB) are important microorganisms for the food industry due to their functional activity, as starters and potential probiotic strains. With that in mind, we explored the LAB diversity in raw buffalo milk, screening for novel potential probiotic strains. A total of 11 strains were identified by combination of MALDI-TOF and partial 16S rDNA sequencing and selected as potential probiotic candidates. Bacteria innocuity assessment was performed by determining antimicrobial susceptibility and the presence of virulence factors. Antagonism activity against Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes and Staphylococcus aureus was assessed, as well as milk proteolytic activity and exopolysaccharides production. Seven strains were identified as innocuous and two of them, Lactobacillus rhamnosus LB1.5 and Lactobacillus paracasei LB6.4 were selected for further probiotic potential analyses. Both strains demonstrated adhesion ability to Caco-2 cells, coaggregated with S. aureus and E. coli and maintained cell viability after gastrointestinal simulation in vitro, suggesting their probiotic potential. Furthermore, the transcriptional response of Lact. rhamnosus LB1.5 and Lact. paracasei LB6.4 to in vitro acid stress was assessed by RT-qPCR targeting seven genes related to adhesion, aggregation, stress tolerance, DNA repair and central metabolism. The association between the transcriptional responses and the maintenance of cell viability after gastrointestinal simulation highlights the genetic ability as probiotic of the two selected strains. Finally, we have concluded that Lact. rhamnosus LB1.5 and Lact. paracasei LB6.4 are important probiotic candidates to further in vivo studies.

Considering the need for reduction in insecticide use, we studied the potential for antibiosis and the potential for antixenosis in seven highly yielding winter Brassica napus L. cultivars against Myzus persicae (Sulz.). We found evidence for antixenosis, i.e., disruption in probing in non-phloem tissues and a failure in reaching sieve elements in cultivar ‘Alister’. We found evidence for antibiosis, i.e., reduced ability of the plant to serve as a host, in cultivar ‘Florida’. On ‘Alister’ and ‘Florida’, net reproduction and reproductive period duration of M. persicae were the lowest of all studied cultivars. ‘Adriana’, ‘Andromeda’, ‘Gladius’, and ‘Kolumb’ are intermediately susceptible to M. persicae infestation with medium values of net reproduction and reproduction period duration, and slight disturbances in aphid probing and feeding. ‘Artoga’ is highly susceptible. On ‘Artoga’, reproduction period was the longest, daily fecundity and net reproduction of M. persicae were highest, and probing and feeding behaviors were unaltered. Glucoallysin, glucobrassicanapin, gluconapin, gluconapoliferin, progoitrin, glucobrassicin, and 4-OH-glucobrassicin occurred in the leaves of all rapeseed cultivars in similar quantities and proportions and did not affect aphid performance and phloem sap ingestion by M. persicae.

Plant resistance to phytophagy is one of the pillars of integrated pest management. Five wild rice accessions viz. IRGC99577, IRGC104646, IRGC105270, IRGC105275, CR100204 along with susceptible (TN1) and resistant (Ptb33) controls were studied for levels of antibiosis resistance and their defense response to brown planthopper (BPH), Nilaparvata lugens (Stal) (Hemiptera: Delphacidae) feeding. Parameters involved in antibiosis resistance viz., honeydew excretion, nymph emergence, nymph survival and development duration and the potential role of antioxidant enzymes viz. superoxide dismutase (EC 1.15.1.1), peroxidase (EC 1.11.1.7), catalase (EC 1.11.1.6), ascorbate peroxidase (EC 1.11.1.11) and H2O2 content in imparting antibiosis against BPH was studied during wet (Kharif) crop seasons of 2017 and 2018. Increased level of antioxidant enzymes were recorded after BPH infestation both in leaf blade and sheath in IRGC99577. Higher induced level of peroxidase was observed in Ptb33 and IRGC99577. Maximum percent increase in H2O2 content after insect infestation was observed in IRGC104646 and CR100204 accessions. The correlation between nymph emergence and superoxide dismutase, peroxidase and H2O2 was significantly negative (r = −0.99, −0.89, −0.93, respectively), while, it was significantly positive with catalase and ascorbate peroxidase (r = 0.99 and 0.98, respectively). Enhanced activities of enzymes may impart resistance in selected accessions against BPH as indicated by correlation and regression analysis. IRGC99577 has come out a potential source of resistance against BPH, which could be used in breeding programmes to develop BPH resistant varieties.

M18 strain of Streptococcus salivarius is a bacterial replacement probiotic that has been suggested for use in the oral cavity. Here, we have shown that S. salivarius M18 cell-free supernatant reduced the growth of the two most common human pathogens Pseudomonas aeruginosa and Klebsiella pneumonia and sensitized the pathogenic bacteria to antibiotic. Besides, the supernatant inhibited biofilm formation of P. aeruginosa drastically. For pinpointing the biomolecular changes that occurred in P. aeruginosa incubated with the probiotic supernatant, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy was used. Unsupervised learning algorithms, principal component analysis (PCA) and hierarchical cluster analysis (HCA), and intensity analyses of individual spectral bands exhibited comprehensive alterations in the polysaccharide and lipid contents and compositions of P. aeruginosa cultivated with S. salivarius M18 cell-free supernatant. These results indicate that S. salivarius M18 has the potential for the prevention or alleviation of different pathogen-induced infections along with the infections of oral pathogens.

Background Probiotics have been reported to reduce total cholesterol levels in vitro, but more evidence is needed to determine the clinical relevance of this activity. Chinese traditional fermented pickles are a good source of lactic acid bacteria. Therefore, pickle samples were collected for screening lactic acid bacteria based on their ability to survive stresses encountered during gastrointestinal passage and cholesterol reducing potency. Results Seventy five lactic acid bacteria strains were isolated from 22 fermented pickles. From these bacteria, Lactobacillus plantarum E680, showed the highest acid (85.25%) and bile tolerance (80.79%). It was sensitive to five of the eight antibiotics tested, inhibited the growth of four pathogenic bacteria, and reduced the total cholesterol level by 66.84% in broth culture. In vivo testing using hypercholesterolemic mice fed high-fat emulsion, independent of food intake, found that L. plantarum E680 suppressed body weight gain and reduced total cholesterol and low-density lipoprotein cholesterol levels, with no effect on high-density lipoprotein cholesterol. Conclusions Chinese traditional fermented pickles are a good source for probiotics. L. plantarum E680, isolated from pickles, was acid and bile tolerant, sensitive to antibiotics, and reduced cholesterol levels both in vitro and in vivo. Based on these results, L. plantarum E680 may have potential as a novel probiotic for the development of cholesterol-lowering functional food.

Summary Interspecies bacterial competition may occur via cell‐associated or secreted determinants and is key to successful niche colonization. We previously evolved Pseudomonas aeruginosa in the presence of Staphylococcus aureus and identified mutations in the Wsp surface‐sensing signalling system. Surprisingly, a ΔwspF mutant, characterized by increased c‐di‐GMP levels and biofilm formation capacity, showed potent killing activity towards S. aureus in its culture supernatant. Here, we used an unbiased metabolomic analysis of culture supernatants to identify rhamnolipids, alkyl quinoline N‐oxides and two siderophores as members of four chemical clusters, which were more abundant in the ΔwspF mutant supernatants. Killing activities were quorum‐sensing controlled but independent of c‐di‐GMP levels. Based on the metabolomic analysis, we formulated a synthetic cocktail of four compounds, showing broad‐spectrum anti‐bacterial killing, including both Gram‐positive and Gram‐negative bacteria. The combination of quorum‐sensing‐controlled killing and Wsp‐system mediated biofilm formation endows P. aeruginosa with capacities essential for niche establishment and host colonization.

A strain named as Pseudomonas aeruginosa 2016NX1, which could produce phenazine and cereusitin, was isolated from the root of Millettia specisoa. Phenazines were extracted, isolated and purified by chloroform, thin-layer chromatography, column chromatography and high-performance liquid chromatography. Then the purified materials were identified by analysis of nuclear magnetic resonance. The major yellow component is 1-hydroxyphenazine and the minor blue component is cereusitin A. The tests of antimicrobial activity of yellow component showed that the growth of several common plant pathogenic fungi and bacteria (such as Cochliobolus miyabeanus, Diaporthe citri, Salmonella sp., Klebsiella oxytoca) could be strongly inhibited. This study suggested that Pseudomonas aeruginosa strain 2016NX1 had a significant potential for biological control of phytopathogenic fungi. SIGNIFICANCE AND IMPACT OF THE STUDY: In this study, one bioactive substance from Pseudomonas aeruginosa 2016NX1 was identified and its antimicrobial activity was verified. This study demonstrated that one bioactive substance from P. aeruginosa can strongly inhibit the growth of plant pathogenic fungi and bacteria. This study suggested that P. aeruginosa strain 2016NX1 has a significant potential for biological control of phytopathogenic fungi.

The objectives of this study were to isolate lactic acid bacteria (LAB) from a raw Moroccan camel milk collected after the incorporation of a specific Argane by-products diet, and to investigate their technological properties as well as their probiotic features. The molecular identification of the isolates indicated that they belong to Weissella confusa, Weissella cibaria or Enterococcus durans species. Our results revealed that the tested isolates have a fast acidifying ability (values ranging between 0.045 ± 0.01 to 0.93 ± 0.01 after only 4 h incubation), important proteolysis, autolysis, lipolytic activities and an important diacetyl and exopolysaccharides production. All these isolates demonstrated a high tolerance to gastrointestinal conditions, namely to gastric simulated juice (survival rate ranged between 75.05 ± 7.88 and 85.55 ± 1.77%) and to bile salts (survival rate between 42.79 ± 1.11 and 82.75 ± 1.01%). The autoaggregation, hydrophobicity and antioxidant activity mean values of the isolates were 13.26-41.16%, 13.23-54.47% and 47.57-63.31%, respectively. Importantly, LAB cultures exhibited antibacterial activity against Gram-negative and Gram-positive pathogenic bacteria and none of the tested isolates presented antibiotic resistance, haemolytic or DNase activities. This study revealed interesting properties for LAB isolated and supported their utilization as autochthone starters for camel milk fermentation that represent a challenge process. These results presented as well the probiotic potential for a possible human consumption.

Indonesian kefir grains are potential sources of lactic acid bacteria (LAB) that may act as probiotics with specific functional properties. In this study we explored the potential of the probiotic and cholesterol-lowering effect of LAB isolated from Indonesian kefir grains obtained from Bogor, Bandung, Jakarta, and Yogyakarta. The results revealed that 10 isolates showed considerable survivability at low pH and bile salt with total cell reduction of ~3 log colony-forming units per milliliter after exposure to pH 2.5 and 0.5% (w/v) bile salt for 1 and 3 h, respectively. All strains exhibited strong antimicrobial activities against pathogenic bacteria and were sensitive to a wide spectrum of antibiotics but exhibited weak bile salt hydrolase activity. Identification based on 16S RNA suggested that nine isolates were Lactobacillus kefiri and one was Lactobacillus rhamnosus. The ability of the isolates to reduce cholesterol from the media varied, ranging from 22.08% to 68.75% with the highest reduction shown by L. kefiri JK17. The ability to remove cholesterol from the media decreased greatly in resting and dead cells, ranging from 14.58% to 22.08% in resting cells and from 7.89% to 18.17% in dead cells. It can be concluded that Indonesian kefir grains contain LAB potentially acting as probiotics capable of reducing cholesterol. The cholesterol-lowering effect especially occurs when the cells are metabolically active.

The occurrence of multidrug-resistant pathogenic bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Acinetobacter baumannii (MDRAB), extended-spectrum β-lactamase (ESBL) Escherichia coli, and Pseudomonas aeruginosa, has become a serious problem in animals and public. The objective of this study was to identify and isolate lactic acid bacterial (LAB) strains from the intestinal tracts of pigs and feces of dogs and then characterize them as potential probiotics with antimicrobial activity against multidrug-resistant pathogenic bacteria. In a preliminary isolation screening, 45 of 1167 isolated LAB strains were found to have anti-S. aureus ATCC 27,735 activity. Using 16S rDNA and 16S-23S rDNA intergenic spacer region (ISR) sequences, five of these isolates were further identified as Lactobacillus animalis 30a-2, Lactobacillus reuteri 4-12E, Weissella cibaria C34, Lactococcus lactis 5-12H, and Lactococcus lactis 6-3H. Antimicrobial substance assays suggest that the L. lactis 5-12H, L. lactis 6-3H, L. animalis 30a-2, L. reuteri 4-12E, and W. cibaria C34 strains might produce bacteriocins and hydrogen peroxide (H2O2) as antimicrobial substances. The L. animalis 30a-2 and W. cibaria C34 strains were further characterized for probiotic properties and shown to have high acid and bile salt tolerance. Additionally, they have broad antimicrobial spectra, and can significantly repress the growth of all of the tested strains of MRSA isolates, some MDRAB, ESBL E. coli, and P. aeruginosa isolates, along with food-borne pathogenic bacteria such as Bacillus cereus ATCC 11778, Listeria monocytogens ATCC 19111, Salmonella spp., Shigella spp., and Yersinia enterocolitica BCRC 12986. This is the first report of H2O2-producing L. animalis 30a-2 and W. cibaria C34 isolated from the intestinal tracts of pigs and feces of dogs that have good antimicrobial activity against multidrug-resistant and food-borne pathogenic bacteria and have excellent probiotic properties.

To establish and maintain an ecological niche, bacteria employ a wide range of pathways to inhibit the growth of their microbial competitors. Some of these pathways, such as those that produce antibiotics or bacteriocins, exert toxicity on nearby cells in a cell contact-independent manner. More recently, however, several mechanisms of interbacterial antagonism requiring cell-to-cell contact have been identified. This form of microbial competition is mediated by antibacterial protein toxins whose delivery to target bacteria uses protein secretion apparatuses embedded within the cell envelope of toxin-producing bacteria. In this review, we discuss recent work implicating the bacterial Type I, IV, VI, and VII secretion systems in the export of antibacterial 'effector' proteins that mediate contact-dependent interbacterial antagonism.

The bacterium-bacterium interaction between pathogenic and probiotic Enterococcus as well as the bacterium-host interaction between Enterococcus and intestinal epithelium has drawn increasing attentions, but the influence of those interactions on host pregnancy remains largely unexplored. In the present study, we evaluated the effects of probiotic E. faecalis Symbioflor 1 or/and pathogenic E. faecalis OG1RF on the miscarriage of pregnant mice. Using in vitro assays of competition and exclusion and displacement, antagonistic property of E. faecalis Symbioflor 1 against E. faecalis OG1RF was observed, and the former inhibited the translocation of the later in vivo. The rate of miscarriage induced by E. faecalis OG1RF challenge was significantly reduced by 28% with E. faecalis Symbioflor 1 intervention; and the tissue integrity of ileum, colon, uterus, and placenta and placental blood cell density in pregnant mice were drastically improved by such probiotic intervention. Compared with the controls, probiotic intervention significantly upregulated the level of IL-10 and TGF-β, downregulated levels of IFN-γ, and increased progesterone level that reversed the trend of being Th1 predominance state reported for adverse pregnancy outcome at early pregnancy stage. In conclusion, E. faecalis Symbioflor 1 decreased the translocation of E. faecalis OG1RF, prevented pathogen-induced tissue damage, and changed Th1-Th2 homeostasis toward Th2 predominance during early pregnancy resulting in decreased miscarriage. KEY POINTS: •The mechanism of how probiotic E. faecalis Symbioflor 1 improves pregnancy of mice • Influence of interactions of pathogenic and probiotic Enterococcus on host pregnancy • E. faecalis Symbioflor 1 change Th1-Th2 homeostasis toward Th2 predominance.

Gram-negative bacteria secrete outer membrane vesicles (OMVs) that play critical roles in intraspecies, interspecies, and bacteria-environment interactions. Some OMVs, such as those produced by Pseudomonas aeruginosa, have previously been shown to possess antimicrobial activity against competitor species. In the current study, we demonstrate that OMVs from Burkholderia thailandensis inhibit the growth of drug-sensitive and drug-resistant bacteria and fungi. We show that a number of antimicrobial compounds, including peptidoglycan hydrolases, 4-hydroxy-3-methyl-2-(2-non-enyl)-quinoline (HMNQ) and long-chain rhamnolipid are present in or tightly associate with B. thailandensis OMVs. Furthermore, we demonstrate that HMNQ and rhamnolipid possess antimicrobial and antibiofilm properties against methicillin-resistant Staphylococcus aureus (MRSA). These findings indicate that B. thailandensis secretes antimicrobial OMVs that may impart a survival advantage by eliminating competition. In addition, bacterial OMVs may represent an untapped resource of novel therapeutics effective against bio-film-forming and multidrug-resistant organisms.

Large scale germplasm screening for Chilo partellus resistance in maize is solely based on visual scoring of damage by leaf injury rating (LIR), where the accuracy in judging a genotype comes by experience of the person, who logically integrate certain symptoms such as levels of growth retardation. Since the pest spends more than half of its larval period damaging the stalk, a quantitative phenotyping method that gives weightage to stalk resistance is required. To explore the traits governing stalk resistance, stalk infestation behaviour of C. partellus was studied first. It was found that first instar C. partellus larva is exclusive whorl feeder, second instar is the transition stage which disperse to infest stalk, and third instar onwards are exclusive stalk borers. To access the stalk, larva tends to penetrate the second above ground internode (seventh internode of maize plant) of V6–10 stage maize. Thus, penetration resistance (PR) of seventh internode was hypothesized to be the characteristic resistance trait. Twenty elite maize breeding lines were evaluated for PR of rind (RPR) and pith (PPR) of seventh internode in V6–7, V8–9 and V10–11 stage plants by TA + Di Texture Analyzer. Significant negative correlation of LIR with RPR of all plant stages and with PPR of V6–7 stage plants suggests the ability of seventh internode to resist larval penetration would confer tolerance to C. partellus. The trait was also found a strong predictor of antibiosis, by affecting the biology and behaviour of C. partellus larva. Thus, PR of seventh internode is proposed to be the trait for phenotyping stalk resistance to C. partellus in maize, whose deployment could lead to selection of genotypes which are resistant to stalk lodging also.

Clonostachys rosea is a promising saprophytic filamentous fungus that belongs to phylum Ascomycota. Clonostachys rosea is widespread around the world and exists in many kinds of habitats, with the highest frequency in soil. As an excellent mycoparasite, C. rosea exhibits strong biological control ability against numerous fungal plant pathogens, nematodes and insects. These behaviours are based on the activation of multiple mechanisms such as secreted cell-wall-degrading enzymes, production of antifungal secondary metabolites and induction of plant defence systems. Besides having significant biocontrol activity, C. rosea also functions in the biodegradation of plastic waste, biotransformation of bioactive compounds, as a bioenergy sources and in fermentation. This mini review summarizes information about the biology and various applications of C. rosea and expands on its possible uses.

The human gut consists of > 1000 different bacterial species for the smooth functioning of the gut. In normal conditions, the antioxidant system present in cells minimize the effects of reactive oxygen species. Upon exposure to antibiotics, there is a rise in ROS level which induces oxidative stress to the cells, ultimately killing the cells. Two broad-spectrum antibiotics, streptomycin and gentamicin at a concentration of 50 µM and 25 µM, were treated with Bacillus subtilis SRMIST201901 (MN726522) and B. cereus SRMIST201902 (MN726923); the treatment reduced the cell counts. Considering the bacterial defense property which relies on the antioxidant mechanism, in this study, we have reported an antioxidant peptide (GM15) derived from glutathione oxidoreductase of spirulina (or called cyanobacteria) Arthrospira platensis (Ap) which reduced the intracellular oxidative stress. Cellular ROS detection was confirmed by fluorescent-associated cell sorting (FACS) using the DCFDA dye. Resazurin dye test also confirmed the activity of peptide on the growth of the Bacillus sp. Based on the results obtained, it was concluded that there was a significant (P

Probiotics can stabilize gut flora, regulate intestinal immunity and protect the host from enteric diseases; however, their roles in oral health have received little attention compared to their roles in gut health. Nowadays, the prevalence of sugar-sweetened foods and abuse of antibiotics contribute towards dysbiosis of oral microbiota and drug resistance development in oral pathogens, resulting in various intractable oral diseases. We screened the antibacterial activities of viable and heat-killed probiotic strains against the oral pathogens Streptococcus mutans, Porphyromonas gingivalis, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans. The probiotic strains Lactobacillus salivarius subsp. salicinius AP-32, L. rhamnosus CT-53, L. paracasei ET-66 and Bifidobacterium animalis subsp. lactis CP-9 displayed strong antipathogenic activities, whereas heat-killed AP-32, CT-53 and ET-66 displayed high levels of pathogen inhibition. The antibacterial activities of these probiotics were not associated with their H2 O2 production; L. acidophilus TYCA02 produced high levels of H2 O2 but merely exhibited moderate antibacterial activities. Oral tablets containing probiotics showed positive inhibitory effects against oral pathogens, particularly those containing viable probiotics. Our results indicate that probiotics prevent the growth of oral pathogens and improve oral health, providing insights into the antipathogenic efficacy of different probiotic species and their potential role in functional foods that improve oral health. SIGNIFICANCE AND IMPACT OF THE STUDY: Our study provides insights into the antipathogenic efficacy of different probiotic species and their potential roles in developing functional foods to improve oral health. We showed that the probiotic strains Lactobacillus salivarius subsp. salicinius AP-32, L. rhamnosus CT-53, L. paracasei ET-66 and Bifidobacterium animalis subsp. lactis CP-9 have great potential for use in the development of functional foods to improve oral health. Since active probiotics may provide strong and long-term protection, the development of functional food products should favour the use of viable bacteria.

The search for new, powerful antimicrobials is essential to respond to the current worldwide spread of antibiotic-resistant pathogens. Sponge-associated bacteria have great potential for production of antimicrobials against resistant and multidrug resistant (MDR) pathogenic bacteria, but only few species of the Class Homoscleromorpha have been screened for these activities so far. The aim of this study was to isolate and identify sponge-associated bacteria active against antibiotic-resistant pathogens from sponges of classes Homoscleromorpha and Demospongiae. By employing five different growth conditions, a total of 239 colony-forming units were isolated and remained viable. Among these, 17 (7.1%) isolates presented antimicrobial activity against pathogenic and (multi)drug resistant bacteria including vancomycin-resistant Enterococcus faecalis, Escherichia coli, Citrobacter freundii, Klebsiella penumoniae, Staphylococcus spp. and Streptococcus spp. Bioactive bacteria belonging to genera Bacillus and Vibrio were identified at species level and the DNA fingerprint patterns showed that strains of the same genus were not clonally related. The most active strains belong to genus Bacillus and were isolated from Oscarella sp., Plakina cyanorosea and Chondrilla caribensis. Our results show for the first time that sponge-associated strains of Bacillus pumilus and Bacillus muralis have high anti-MDR activity, and that the Homoscleromorpha may be a better source of such anti-MDR active bacteria than the Demospongiae. These results suggest that marine bacteria associated to homoscleromorph sponges may be an interesting source of new antimicrobial substances with biotechnological potential to treat infections caused by antibiotic-resistant bacteria.

This study describes Chromobacterium violaceum's use of extracellular membrane vesicles (MVs) to both solubilize and transport violacein to other microorganisms. Violacein is a hydrophobic bisindole with known antibiotic activities against other microorganisms. Characterization of the MVs found they carried more violacein than protein (1.37 ± 0.19-fold), suggesting they may act as a reservoir for this compound. However, MVs are not produced in response to violacein - a ΔvioA isogenic mutant, which is incapable of making violacein, actually produced significantly more MVs (3.2-fold) than the wild-type strain. Although violacein is insoluble in water (Log Poctanol:water = 3.34), 79.5% remained in the aqueous phase when it was present within the C. violaceum MVs, an increase in solubility of 1740-fold. Moreover, tests with a strain of Staphylococcus aureus showed MV-associated violacein is bactericidal, with 3.1 mg/l killing 90% of S. aureus in 6 h. Tests with the ΔvioA MVs found no loss in the S. aureus viability, even when its MVs were added at much higher concentrations, demonstrating violacein is the active component within the wild-type MVs. In conclusion, our study clearly demonstrates C. violaceum produces MVs and uses them as vehicles to solubilize violacein and transport this hydrophobic antibiotic to other microbes.